One‐Step Polymeric Melt Encapsulation Method to Prepare CsPbBr 3 Perovskite Quantum Dots/Polymethyl Methacrylate Composite with High Performance

Abstract All‐inorganic CsPbBr 3 perovskite quantum dots (PQDs) exhibit excellent photoelectric properties and application prospects in the field of light‐emitting diodes (LEDs) and display devices. However, these possess poor long‐term stability to UV irradiation, water, heat, and oxygen. Using polymethyl methacrylate (PMMA) as the matrix along with CH 3 (CH 2 ) 16 COOCs, [CH 3 (CH 2 ) 16 COO] 2 Pb, and KBr as the perovskite sources, CsPbBr 3 PQDs/PMMA composites are for the first time prepared via an in situ polymeric melt encapsulation method. Special attention is paid to the effects of synthesis conditions on the photoluminescent quantum yield (PLQY) of the composites. The optimized CsPbBr 3 PQDs/PMMA composite reveals excellent performance with ≈82.7% PLQY and ≈18.6 nm full width at a half‐maximum (FWHM). In particular, after 90 h of UV irradiation or 35 days of heating at 60 °C, the luminous intensity remains almost unchanged. In addition, after soaking in water for 15 days, it retains up to ≈53% of the initial luminous intensity, meaning that the composite possesses long‐term stability to UV irradiation, heat, and water. The as‐prepared white LED (WLED) based on the composite evidences the wide color gamut (126.5% National Television System Committee (NTSC)) and a luminous efficiency of 32 lm W −1 . This work offers a novel, easily industrialized one‐step, and solvent free route for low‐temperature synthesis of all‐inorganic PQDs with broad application prospects.